[0:00] (gentle music) [0:01] - Erosion is a natural part of any stream system. [0:04] As streams meander, they're constantly depositing sediment [0:07] and eroding sediment in other places. [0:09] In some instances, we do have areas [0:12] that the erosion's getting too bad, [0:14] and this is one of those cases. [0:16] We have a large cut bank on an outer edge of the stream, [0:19] and as this sediment is eroded, one, it enters the stream. [0:23] That's not great for the stream ecosystem, [0:25] if it's too high of a sediment load. [0:27] And then two, as this erodes, [0:29] it's gonna start creeping upland. [0:31] And in this case, we have a path [0:33] on the upland side of things. [0:34] And as that erosion continues to happen, [0:37] it starts to impact and conflict [0:39] with the position of that path. [0:41] The fix for these sort of erosion problems [0:43] on a stream is pretty complicated. [0:45] One, you have to go in and fix the erosion [0:48] that's already occurred, so you do some digging out [0:50] and make sure that you're not creating the problem worse. [0:53] So, we do a lot of that work in the winter, [0:55] and then you have to stabilize it [0:56] so you rebuild the stream bank [0:58] to have either some rock bottoms [1:01] or some fabric that helps stabilize things. [1:04] And in some instances, when you have such a small area [1:07] from the infrastructure that's up there, [1:10] in this case, a path to the stream, [1:12] it could make sense to kind of [1:13] scoot the infrastructure over a little bit, [1:15] because you wanna give that stream some space [1:17] so it can have its natural meander curve come back. [1:19] And we don't run into this problem in the future [1:21] where that conflict happens. [1:24] Because Moir and Central Park are located [1:26] in the Nine Mile Creek Valley, [1:28] there are a lot of steep slopes [1:30] and steep slopes are prone to erosion. [1:32] It's not necessarily bad [1:33] that there's some erosion here and there. [1:35] That's a natural process. [1:37] But in some areas, this erosion's become a problem. [1:40] And so, as part of the Nine Mile Creek [1:42] Corridor Renewal Project, [1:44] we want to find those problematic areas [1:47] and we come up with a fix. [1:49] It could be rebuilding the slope, [1:51] it could be just keeping an eye on things, [1:53] it could be adding new infrastructure. [1:56] There's a lot of old infrastructure [1:57] that's already through the parks, [1:58] or it could be as simple as just adding new vegetation [2:01] and all those roots really holding the slope together. [2:04] Another big issue with erosion [2:06] in the valley system is gullies, [2:08] and that's where the land kind of creates [2:10] that V shape and funnels water down through it. [2:13] Because it has a lot more flowing water, [2:15] it gets these big head cuts that start to form, [2:18] and that's where the water starts to kind of waterfall [2:20] and that starts to cut upstream. [2:22] So, what we wanna do is we wanna find these gullies. [2:26] We wanna make sure that they aren't experiencing [2:28] these significant erosion occurrences, [2:30] and if they are, whether or not [2:32] we need to fix them and how to fix them. [2:35] Erosion and slope management, [2:37] it's not particularly glamorous, [2:39] but it's a really important component [2:41] of managing the lower creek corridor. [2:44] We wanna make sure that we are putting the investment in now [2:47] to ensure that some of those areas that have bad erosion [2:51] don't continue into the future, [2:52] and that we're doing this work in coordination [2:56] with a lot of the other projects [2:57] that are happening with the renewal project. [2:59] And that could be vegetation management, [3:01] wetland restoration, and stream management. [3:04] Doing those things together [3:06] really helps maximize the impact of our efforts. [3:10] (gentle music)